Curved Box‐Girder Bridges

Based on the curvilinear coordinate system, the spline finite strip method is extended to the elasto‐static analysis of circular and noncircular box‐girder bridges. As the curvature effect cannot be ignored, the webs of the bridges have to be treated as thin shells and the flanges as flat curved plates. The shape functions for the description of the displacement field (radial, tangential, and vertical displacements) are given as products of B‐3 spline functions in the longitudinal direction and piecewise polynomials in the other direction. The stress‐strain and stiffness matrices can then be formed as in the standard finite element method. Three examples of box‐girder bridges of different geometrical shapes are employed to demonstrate the accuracy and versatility of the method. Compared to the finite element method, this method yields considerable savings in both computer time and effort, since only a small number of unknowns are generally required in the analysis.